Conventional lighting systems including fluorescent lamps have been used for decades but are expected to be replaced by light-emitting diode (LED)-based luminaries in the future. Typically, such LED-based luminaries include a plurality of LEDs.
White light may be obtained from an LED using a blue LED and a wavelength converting material, also known as phosphor, which absorbs part of the blue light emitted by the LED and reemits light of longer wavelength(s). For reasons of efficacy it is preferable to have the wavelength material arranged at a distance from the LED, in a so-called remote configuration.
In the field of lighting for interior and exterior, there is an increasing need for lighting systems having a specific design and function. The purpose of lighting may be the creation of a general illumination or to focus the light on certain areas or objects. For example, in an office environment it is often desirable to provide direct lighting for workspaces as well as indirect lighting for general illumination. Hence it would be desirable to provide a lighting system which has a specific light distribution.
For this purpose, to obtain a desired beam shape, combinations of refractive and or diffractive optical elements have been used. However, such optical elements are usually expensive and may decrease the system efficiency due to optical losses.
Hence, there is still a need in the art to provide an improved lighting system which has a specific light distribution.